In the summer of 2006, as the Iranian-backed Hezbollah fought off Israelis in Lebanon and President Mahmoud Ahmadinejad faced down President George Bush, a bus full of Iranian pilgrims left Tehran on a journey to the holy city of Karbala, deep inside a shattered Iraq.

Pilgrimage to Karbala follows this intense journey into the heartlands of Shia Islam, revealing how two ancient crimes – the murder of Muhammad’s grandson and the disappearance of a six-year-old imam – became the founding legends of Shiism and still shape events in the Middle East today. The film is followed by Daljit Dhaliwal’s interview with Professor Vali Nasr, author of The Shia Revival: How Conflicts Within Islam Will Shape the Future.